While searching Newspapers.com for ‘Marion Crawford,’ I came across the following G.A.R. article.

G.A.R.

We are under obligations to Mr. J. L. Slaven for the names of the members of Lewis Post, of this city, who contemplate attending the encampment at St. Louis. Thos of the Post who attend will leave this city on Sunday, September, 25th. So far as is known at present the following members will attend.

H. Juneau
Dr. D. D. Rose
N. P. Laughton
W. J. Howard
Marion Crawford
Wm. Tilghman
P. R. Hobble
C. C. Routzhan
J. L. Slaven
Col. J. H. Straughn

The above list not only mentions Marion Crawford but his brother-in-law, Dr. Daniel Rose. Further information about Marion Crawford’s attendance at the encampment have not been found. Many newspapers contain an extensive account of the encampment.

This YouTube video provides a brief history of the G.A.R. in St. Louis